Abstract
Purpose :
To employ centile analysis for assessing the treatment efficacy of a clinical trial for myopia control, and to quantify differences in the natural history of myopia progression in the treatment group, control group and conventional clinical practice.
Methods :
Gender and age specific population centiles for refraction and annual progression were calculated for the 113 subjects recruited for the MiSight® 1 day trial (Chamberlain et al., OVS 2019) in Western trial sites (Portugal, United Kingdom and Canada). The reference population used for centile calculation comprised 4650 Irish children aged 8-17, from an anonymized sample of optometric health records where refraction data was available over multiple visits (mean 5.32, range 3-23).
Results :
The partial MiSight control group showed no significant change in centile values of spherical equivalent refraction over three years (mean change -0.9, 95% CI -2.8 to 1.1) indicating that they were following the natural history pattern seen in the population based sample, whereas the treatment group showed a change of -10.7 (95% CI -12.7 to -8.7, Fig. 1). First year annual myopic progression in the control group was similar to that seen in the population sample with a mean centile of 58.4 (95% CI 53.3 to 63.5). In the treatment group the mean progression centile value was significantly lower at 32.6 in year 1 (95% CI 26.9 to 38.4), a difference that persisted over the three years of the trial (Wilcoxon, P= 0.027). Histograms of progression centiles show that the treatment group displayed a reduction in fast progressors, an effect present in both young (<= median age) and older subjects (> median age) (Kolmogorov-Smirnov two-sided test, treatment vs control young P < 0.00001, older group P < 0.0005, Fig. 2).
Conclusions :
This analysis indicates that the MiSight lens can alter the natural history of myopia. There was a reduction in the proportion of fast progressors in both the younger and older treated subjects. Population based centile analysis offers the prospect of monitoring the treatment efficacy of myopia control interventions outside a clinical trial and allows individual clinical practice patients to be benchmarked against the results obtained during the MiSight trial.
This is a 2020 ARVO Annual Meeting abstract.